Japanese Patent Publication 2005-79195 discloses a multi-channel measuring apparatus for connecting to a fuel cell stack. The apparatus disclosed in the publication is provided with two types of terminal-side connectors different from each other in number of poles. The number of poles of the terminal-side connector of a second type is designed to be equal to or greater than the number of extra fuel cells when the terminal-side connectors of a first type are connected to fuel cells of the fuel cell stack and is designed to be smaller than the number of poles of the terminal-side connector of the first type.
However, there are the following problems with the conventional multi-channel measuring apparatus for connecting to a fuel cell stack:                (a) When the number of poles of the terminal-side connector of the second type is designed to be greater than the number of the extra fuel cells when the terminal-side connectors of the first type are connected to fuel cells of the fuel cell stack (i.e., when there are poles not connected to the fuel cells of the fuel cell stack in the terminal-side connector of the second type), due to the extra poles of the terminal-side connector of the second type, the terminal-side connector of the second type is partially of no use and causes a disadvantage in the multi-channel measuring apparatus with respect to space.        (b) When the number of poles of the terminal-side connector of the second type is designed to be equal to the number of the extra fuel cells when the terminal-side connectors of the first type are connected to the fuel cell of the fuel cell stack, there is no extra pole not connected to the fuel cells of the fuel cell stack in the terminal-side connectors of the second type. However, since the pole number of the terminal-side connector of the second type changes according to a change in the number of the fuel cells of the fuel cell stack and, therefore, is not constant, when the number of fuel cells of the fuel cell stack is changed, the terminal-side connector has to be modified (e.g., redesigned).        
Patent document 1: Japanese Patent Publication 2004-79195.